Finding the Fourth Proportional to 21,087.72, 31,620.96 and 7,042.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,087.72 : 31,620.96 = 7,042.86 : x
2. Step 2: Convert to fraction form
   21,087.72/31,620.96 = 7,042.86/x
3. Step 3: Cross multiply
   21,087.72x = 31,620.96 × 7,042.86
4. Step 4: Simplify right side
   21,087.72x = 222,701,994.35
5. Step 5: Solve for x
   x = 222,701,994.35/21,087.72
6. Step 6: Final answer
   x = 10,560.74